In the electronic industry much use is made of circuit boards or cards one side of which carries a number of components mounted thereon and the other side of which carries the wiring which interconnects the various components into circuits. Many of the electrical components which may be mounted on such cards are heat sensitive and will not perform properly or will not last for a sufficient life span unless they can be kept cool. In many applications cool air is blown across the surface of the cards in order to dissipate heat, however, as components become smaller enabling higher component density on the cards, and as power requirements for various components become larger, that type of cooling in many cases becomes impractical.
Liquid cooling of electronic components provides many problems which are difficult to resolve. For example, if the cooling liquid is placed directly on the component board, it would short out the electrical connections on the board unless the liquid were absolutely non-conducting. Since it is virtually impossible to prevent contaminations from entering the cooling liquid, it is virtually impossible to prevent a short circuiting of components if the liquid is directly applied. Consequently, techniques have been developed whereby the cooling fluid (liquid or gas) is channeled through a heat sinking component which is placed near the electrical components which are to be cooled. The problem then is to couple the electrical components to the heat sink. At present, potting compounds are generally used for such coupling, the compounds covering the entirety of the surface of the card and all components thereon and are built up to come into intimate contact with the surface of the heat sink. Such potting compounds are not reuseable since they become part of the card itself. Unfortunately, they also tend to contaminate or short out components on the card or otherwise occasionally cause electrical difficulties thereon. Therefore, it is the general object of this invention to provide a cushioning heat transfer pad which will provide intimate contact with each of the components mounted on a circuit board and a heat sink. It is another object of the invention that the coupling pad be reuseable so that as cards are replaced in normal maintenance of a device, the heat transfer pad can be reused from card to card. Further objects include non-contamination and non-shorting of electrical components; economical, easily produced, non-toxic material; must not produce harmful gases at elevated temperatures; must not degrade at continuous operating temperatures; and should be somewhat elastic to allow for variations in component locations from card to card.